An inmate at the U.S. Administrative Maximum Prison (ADX) in Florence, Colorado, pleaded guilty to first degree murder and murder by a life prisoner of a fellow ADX inmate.

Assistant Attorney General Leslie R. Caldwell of the Justice Department’s Criminal Division, Acting U.S. Attorney Bob Troyer of the District of Colorado and Special Agent in Charge Calvin A. Shivers of the FBI’s Denver Division made the announcement.

Richard Santiago, 56, pleaded guilty Thursday before U.S. District Court Judge Robert E. Blackburn of the District of Colorado.  Immediately after the guilty plea, Judge Blackburn sentenced Santiago to serve life in federal prison without the possibility of release.

According to Santiago’s plea agreement and evidence presented at the trial of co-defendant Silvestre Mayorqui Rivera, Santiago and Manuel Torrez were members and Rivera was an associate of the Mexican Mafia.  Torrez and Santiago arrived at ADX in 2000.  On April 21, 2005, shortly after Rivera’s arrival, he and Santiago murdered Torrez while the three were exercising in one of the ADX’s general population unit recreation areas by stomping, kicking and punching Torrez until he was dead. 

Rivera was convicted of first degree murder following a jury trial and was also sentenced to serve life in federal prison without the possibility of release.